nearbyint

基于当前的舍入方向，返回x的舍入值。

接口定义

C interface：

float nearbyintf(float x);

double nearbyint(double x);

参数

参数名	类型	描述	输入/输出
x	在nearbyintf中，x是单精度浮点类型。在nearbyint中，x是双精度浮点类型。	表示输入数据的浮点值。	输入

返回值

返回x的舍入值，x ∈ (-inf, inf)。
输入+0，返回+0。
输入-0，返回-0。
输入±∞，返回±∞。
输入nan，返回nan。

依赖

C: "km.h"

示例

C interface：

    // typical usage
    double x1 = 0.0, x2 = -0.0, x3 = 1.5, x4 = -2.5;
    // special handing
    double a = INFINITY, b = -INFINITY, c = NAN;
    // pnearbyint result
    printf("nearbyint(0.0) = %.15f\n", nearbyint(x1));
    printf("nearbyint(-0.0) = %.15f\n", nearbyint(x2));
    printf("nearbyint(1.5) = %.15f\n", nearbyint(x3));
    printf("nearbyint(-2.5) = %.15f\n", nearbyint(x4));
    printf("nearbyint(INFINITY) = %.15f\n", nearbyint(a));
    printf("nearbyint(-INFINITY) = %.15f\n", nearbyint(b));
    printf("nearbyint(NAN) = %.15f\n", nearbyint(c));
    /* 
     * nearbyint(0.0) = 0.000000000000000
     * nearbyint(-0.0) = -0.000000000000000
     * nearbyint(1.5) = 2.000000000000000
     * nearbyint(-2.5) = -2.000000000000000
     * nearbyint(INFINITY) = inf
     * nearbyint(-INFINITY) = -inf
     * nearbyint(NAN) = nan
     * */

父主题： 函数定义